Vegan Diets: Healthy Or Unhealthy?

Veganism has become an increasingly popular lifestyle choice, with many people adopting it for ethical, environmental, or health reasons. While a vegan diet can offer several health benefits, such as lower heart disease risk and reduced cholesterol levels, there are also potential health risks associated with it.

One of the main concerns is nutritional deficiency. A vegan diet may not provide sufficient amounts of certain essential nutrients, including vitamin B12, omega-3 fatty acids, calcium, zinc, iron, and protein. These deficiencies can lead to various health issues such as anaemia, fatigue, depression, and an increased risk of certain cancers and bone fractures. Additionally, a vegan diet can be restrictive and may require careful planning to ensure adequate nutrient intake.

Some people take veganism to the extreme by adopting a raw food diet, which can further limit nutrient intake and may cause harm if followed for an extended period. It is important for individuals considering a vegan diet to carefully plan their meals and consult healthcare professionals to ensure they are meeting all their nutritional needs.

Nutritional deficiencies

Vitamin B12 deficiency

Vitamin B12 is mainly found in animal products, so vegans are at a higher risk of developing a deficiency. Vitamin B12 is crucial for a healthy nervous system and preventing anaemia. It is recommended that vegans supplement their diet with a high-quality vitamin B12 supplement or include B12-fortified foods in their diet.

Iron deficiency

Iron deficiency, or anaemia, is a common issue for vegans since the form of iron found in plants (non-heme iron) is not as easily absorbed by the body as the iron found in animal products (heme iron). Iron is essential for transporting oxygen in the blood and preventing fatigue. To enhance iron absorption, combine plant-based iron sources with vitamin C-rich foods like oranges, tomatoes, and peppers.

Omega-3 fatty acid deficiency

Omega-3 fatty acids are important for brain health and can help prevent depression. Since the main sources of omega-3 are fish and fish oils, vegans may be at risk of deficiency and subsequent mental health issues. Algae-based omega-3 supplements can help, but they can be expensive and hard to find.

Zinc deficiency

Zinc is essential for a healthy immune system. Vegan diets may lead to low zinc status due to the presence of phytic acid in plant foods, which inhibits the body's ability to absorb zinc. It is recommended that vegans increase their zinc intake to ensure adequate levels.

Calcium deficiency

Dairy-free and vegan diets may result in calcium deficiency since plant-based sources typically contain less calcium than dairy products. Calcium is crucial for bone health, and a long-term deficiency can increase the risk of bone fractures. Fortified plant-based milk or calcium supplements can help prevent this deficiency.

Iodine deficiency

Without seafood or iodised salt in their diet, vegans may not get enough iodine, which is essential for thyroid health. Iodine deficiency can lead to hypothyroidism and other health complications. Including seaweed products or iodised salt in the diet can help prevent this deficiency.

Overall, a vegan diet can be healthy, but it requires careful planning and, in some cases, supplementation to ensure you are getting all the necessary nutrients. It is always a good idea to consult with a healthcare professional or a registered dietitian before making significant dietary changes.

Increased risk of certain cancers

A vegan diet may be associated with a lower risk of certain cancers, such as colon and breast cancer. A study published in the medical journal BMC Medicine found that compared to regular meat-eaters, vegetarians had a lower risk of all cancer sites, including a lower risk of colorectal cancer in men, and a lower risk of postmenopausal breast cancer in women.

However, the study also found that the lower risk of postmenopausal breast cancer in vegetarian women was largely due to their lower BMI, and when BMI was factored in, the risk was no longer statistically significant. The study also found no association between a vegetarian diet and a lower risk of breast cancer in premenopausal women.

Another study found that men who ate plant-based foods had a 22% lower risk of bowel cancer compared to those who ate the least amount of plant-based foods. However, this study found no such link for women.

It is important to note that a vegan diet may also be associated with an increased risk of certain cancers due to nutritional deficiencies. For example, a vegan diet may lead to a deficiency in vitamin B12, which has been linked to an increased risk of certain types of cancer.

Higher rates of depression and anxiety

A vegan diet may be linked to a higher risk of depression and anxiety. However, the evidence is mixed, with some studies reporting no change or a lower risk of depression and anxiety among vegans. A few factors could explain this discrepancy.

Firstly, it's possible that individuals with pre-existing mental health issues may be more inclined to adopt a vegan diet in an attempt to alleviate their symptoms. Secondly, cultural factors could play a role, as observed in the Brazilian study, where meat is a significant part of the cultural heritage, and abstaining from it could lead to feelings of isolation. Lastly, nutrient deficiencies, particularly vitamin B12 and omega-3 fatty acids, which are essential for brain health and mood regulation, could be a factor. These nutrients are predominantly found in animal-based foods, so vegans may need to include fortified foods or supplements in their diet to meet their requirements.

The impact of a vegan diet on mental health is complex and not fully understood. While some individuals report improved mood and reduced anxiety, others experience the opposite. The relationship between diet and mental health is intricate, and other factors, such as personal history, life events, and physical health, also play a role in depression and anxiety.

To ensure a vegan diet supports mental well-being, it's crucial to prioritise whole or minimally processed plant foods and address any nutrient deficiencies. Seeking guidance from a registered dietitian or healthcare professional can help individuals make informed decisions about their diet and mental health.

Poor skin health

A vegan diet can have both positive and negative impacts on skin health. On the one hand, a vegan diet may reduce the risk of certain skin conditions, such as acne, psoriasis, and atopic dermatitis. On the other hand, a poorly planned vegan diet may lead to nutritional deficiencies that can negatively affect the skin.

Positive Impacts of a Vegan Diet on Skin Health

A vegan diet is typically rich in fruits, vegetables, whole grains, nuts, seeds, and legumes, which are good sources of vitamins, minerals, antioxidants, and phytochemicals. These nutrients are beneficial for maintaining healthy skin. For example, vitamin C and E, found in citrus fruits, leafy greens, and nuts and seeds, respectively, can help neutralize free radical damage, promote collagen production, and reduce wrinkles and skin firmness.

A vegan diet can also help reduce the risk of certain skin conditions:

• Acne: Dairy products, particularly milk, have been linked to acne due to their potential to stimulate the synthesis of insulin-like growth factor 1 (IGF-1), which plays a role in acne development. By eliminating dairy, some people may experience a reduction in acne.
• Psoriasis: A vegan diet can be beneficial for psoriasis due to its potential anti-inflammatory properties. Plant-based diets are typically low in saturated and trans fats and arachidonic acid, which are pro-inflammatory, and high in antioxidants and omega-3 fatty acids, which have anti-inflammatory effects.
• Atopic Dermatitis: A vegetarian diet has been found to decrease the severity of atopic dermatitis by reducing peripheral eosinophils and PGE2 synthesis, which are involved in skin inflammation. Additionally, a vegetarian diet can reduce oxidative DNA damage, which is associated with skin inflammation.

Negative Impacts of a Vegan Diet on Skin Health

A poorly planned vegan diet may lead to nutritional deficiencies that can negatively affect skin health. Some of the key nutrients to consider for skin health include:

• Vitamin B12: Deficiency can lead to skin problems such as dark spots, cheilitis angularis (mouth corner eczema), hair loss, eczema, and vitiligo. It is recommended that vegans take vitamin B12 supplements or consume fortified foods.
• Omega-3 Fatty Acids: Omega-3 fatty acids, such as EPA and DHA, are vital for healthy skin hydration, elasticity, and inflammatory responses. These fatty acids are mainly found in fish and shellfish. Vegans may struggle to obtain adequate amounts from plant sources, which primarily contain ALA, a less efficient form of omega-3. It is recommended that vegans consider taking supplements containing algae-based EPA/DHA to ensure adequate intake.
• Iron: Iron deficiency can lead to dry and damaged hair, hair loss, brittle nails, pale skin, itching, and increased susceptibility to skin infections. While vegan diets can be rich in iron, absorption may be an issue. It is recommended to include vitamin C-rich foods or supplements with meals to enhance iron absorption. Good plant sources of iron include beans, lentils, tofu, tempeh, fortified breakfast cereals, nuts, and seeds.
• Zinc: Zinc plays a vital role in skin health, including wound healing, collagen formation, regulating sebum production, and maintaining healthy skin structure. A zinc deficiency can lead to skin problems such as acne and eczema. Vegans should ensure they consume zinc-rich foods, such as nuts, seeds, legumes, and whole grains, or take a supplement if needed.
• Iodine: Iodine deficiency can lead to dry skin, flaking, and hair loss. This can be addressed by adding seaweed to the diet.
• Protein: Proteins are essential for skin health and collagen production. Vegans should ensure they consume enough protein from plant sources, such as beans, lentils, tofu, and tempeh, and combine different protein sources to obtain all the essential amino acids.

In summary, a well-planned and balanced vegan diet that includes a variety of whole foods and addresses potential nutrient deficiencies can have positive impacts on skin health and reduce the risk of certain skin conditions. However, a poorly planned vegan diet may lead to nutritional deficiencies that can negatively affect the skin.

Loss of menstruation

A vegan diet can lead to a loss of menstruation, or amenorrhea, for a variety of reasons.

Low Body WeightResearch shows that people with a meat-free diet are more likely to have a lower body weight. If calorie intake is too low and disordered eating persists, disturbances in menstrual cycle length or amenorrhea may occur. Extreme caloric restriction can affect cycle length or stop menstruation altogether.

Low Iron LevelsIron deficiency is common in women, and a vegan diet may not provide enough iron. Iron is needed to create haemoglobin, a substance in red blood cells that carries oxygen around the body. When iron levels are low, this can lead to anemia, which means there isn't enough oxygen-rich blood flowing through the body.

People with a menstrual cycle are more likely to have anemia due to blood loss during their period. Losing any amount of blood means losing red blood cells. Studies suggest that people who follow plant-based diets could be more at risk of iron deficiency or low iron stores.

Meat contains higher levels of iron than plant-based foods, particularly heme-iron, which is a more absorbable form. Animal-based iron is already in its usable form, so no further processing is required for the body to utilise it.

Low ProgesteroneA vegan diet can cause irregular or heavy periods due to impaired ovulation and low progesterone. Phytoestrogens in grains, seeds, and legumes can have a beneficial anti-estrogen effect, and make periods lighter. However, a high intake of phytoestrogens can potentially impair ovulation and progesterone, leading to heavier periods. A very high intake can even shut down periods in some women.

Nutrient DeficiencyA vegan diet may not provide an adequate supply of nutrients such as zinc, iodine, iron, vitamin A, and taurine. These deficiencies can impair ovulation and cause amenorrhea (lack of periods), anovulation (irregular periods), or heavy periods due to low progesterone.

Extreme ExerciseA vegan diet is often associated with more physical activity, which can also lead to amenorrhea.

Frequently asked questions